The Adenans were the first group of Indians or Native Americans who built mounds in America. The mounds were burial sites for their dead.
the signficance of the process of mound building is that it is a lot like pyrimids but they are built with a flat top instead of a point (us history e2020)
The first known inhabitants of modern-day United States territory are believed to have arrived over a period of several thousand years beginning sometime prior to 15,000 - 50,000 years ago by crossing Beringia into Alaska.[2] [3] Solid evidence of these cultures settling in what would become the US is dated to at least 14,000 years ago.[4]